[frolinmod]

You are not going to see prominences or the chromosphere inexpensively. The least expensive way to view prominences is to purchase a small purpose built Hydrogen Alpha solar telescope such as a Coronado (aka Meade) PST. You do have to be careful if you buy a used PST because while some are good, some are very bad. You need to look through a few before you can judge.

If you're happy viewing the sun in white light, seeing little more than sunspots and the like in the photosphere, then a front mounted filter made with Baader AstroSolar Safety Film (visual ND5) is the least expensive and arguably the best option. Adding a green or red eyepiece filter to that can improve contrast. The Baader Solar Continuum filter is sort of just a narrow band green filter, but some people swear by it for enhancing contrast.